Automatic syringe injector



July 7, 1936.' l

i -'ifDlQKINSON 2,047,010 HAUTOMATKI"SYR'NGYTNJECTOR Filed Jan. 5o, 1955 2 sheets-sheet 2 ,A d k IIIIIIInII/IIIIIIIIIIIIIIIIIIIIIIIIIIlVII w ITN Ess xNvENToR ATTORNEYS Patented July 7, 1936` f n'roMATlo srRINGE {IVNJECTORQV 1s Claini's. (ci. 12s- 1215) This-:invention relates` to'automatic syringe injectors-'andmore 4particularly to an automatic injector which is intendedl for use with a syringe for hypoderniey and intra-muscular injections Wherebythe needle on such syringe may be automaticallyA inserted into the body of thepatient to thel proper dep-th of penetration.. The object of the invention -is to improve thestructureof,

such syringe injectors'so as toimake them more eflicient'and reliable.` i

Automatic injectors of the indicated type `usue ally comprise a holder for an especially constructed oriordinary hypodermic syringe which when released from a set position is plunged downwardly kunder the actionof avspring so =as to cause the needle of lthe syringe to" pierce the skin of the patientv and-project into the fleshy area to be treated. In all such devices, the spring must be suiliciently powerful to effect a rapid plunging action of the needle. Injectors of this type are alsofusually p-rovidedwith a lregulator forl controlling the depth of vpenetration of the needle thereby `making it possible for the patient himself or any lay person to properly inject a medicament into the area@ to be treated. Because of the above mentioned advantages, such syringe injectors are being'used' to an increasing extent by individual lay vusers of. insulin. Existing syringes of-this type have in. common, however, certain disadvantages which ithas become in-v creasingly important-to remove in view of the increasing use of `such syringes by lay users so that the mechanism shall function in a most reliable fashion as to all -of its several ,'functions. The chief disadvantage of the existing syringes, is the fact that the needle vibrates considerably in entering the esh of the patientn In studying the cause of` this unsatisfactorycondition, I have found that the cause of the excessive vibration of the needle lay primarily in the fact that the vibrations which were developed in the support for thesyringe as a result of the swift plunging action of the partswere too definitely transmitted to the syringe vand thence to the needle point.

The sudden abrupt stopping of the swift plungi ing actionof theineedle at the end of its stroke was'also a contributing' cause,though to aimuch lesserK extent. Those prior syringe injectors in which' the syringe holder is` encased within an outer cylinder `possessed in addition the disadvantage that the graduation marks on the syringe barrel were, so far as I am aware, almostgentirely coveredwhen the syringe was inits `normal or i kprojected position so that the user of. one of` such prior devices never knew for a certainty whether he Thepurpose of the presenty invention Ais to pro' v ide an improved automaticsyringe injector construction which will overcome all'the 'above mentioned and,.`other difficulties and particularly to g vinjecting the" proper dosage of the medicant into'fthe penetrated flesh.

provide simplesturdy and satisfactory means which will ,minimize vibration of the syringe in its downward plunging motion,` will guide the needle straight to the'point .where the medicament is to bey injected and will minimizev vibration of 4 the needle in the flesh of the patient. A further object of the invention isfto Aprovide an automatic syringeinjector ofthe stated type in which the parts are so arrangedthat the scale on the syringe'barrel `caribe easily read when the syringe is in its rdownward or projected position.

Other objectsand advantages of the invention .will become apparent from the following description, `taken connection with the accompanying drawings in which I haveshown for the-purposes of illustration, thelpreferred embodiment of my invention. In these'drawings, Fig.,1 is a side elevation` of the device showing the parts in normal or projected position; Fig. 2 is a front elevation of the device partly in section, with'the n parts set to projectthe syringe needle; Fig. 3 is a rear 4elevation of thedevice showing the relationl of the parts in normal position; Fig. 4 is a central vertical section of Fig. 1, the syringe, however being shown in side elevation; Fig. 5 is a View taken along line 5-'5 of Fig. 4; Fig. 6 is a section taken along line 6-6 of Fig. 4; Fig. 7 is a view `similar to Fig. 5 showing the cap rotated through 90 so that the syringe may be removed from lits supporting casing; Fig. 8 is a section similar 4to Fig. 6 with the syringe removed, showing the relation of the parts in the rotated position of the cap; Figs. 9, 10, and 1l are sections taken along the lines 9-9, lll-I0, and II-l I, respectively, of Fig. 4 andFig. 12 is a perspective View of the annulanmember seated under the 2 adapted to receive a hypodermic syringe 3 of ordinaryor special sizerand shape. The'outer cylinder l is provided at its lower end with'an externalanged portion 4 which enables the user to `press the device firmly against the surface of the. skin overthe tissues within which the medicament is to be injected, such flange being preferably roughened at its outer edge to prevent slippage of the ngers of the user. The exterior surface of the cylinder I is also preferably roughened for the same reason. An inwardly extending `flange 5 is provided at the upper end portion of the outer cylinder I for the purpose of guiding the movement of the inner cylindrical member 2 and to serve as a. seat for the upper end of a. coiled spring B which is positioned intermediate the outer and inner cylinders I and 2 and is concentrlcally arranged with relation thereto.

The inner cylinder 2 is provided at its lower end with an outwardly extending flange 'I having an outside diameter slightly less than the inside diameter of the outer cylindrical shell I so that it will readily move within the cylinder I and is adapted to serve as a seat for the lower end of the spring 6. Thus when the inner cylinder 2 is retracted from the outer cylinder I, the spring 6 is compressed between the anges 5 and 1 to yieldingly resist withdrawal of said inner cylinder 2 to its retracted position. 'I'he upper end portion of the inner cylinder 2 is provided with an enlarged annular portion or boss 8 which is adapted to seat the shoulder 9 on the upper end of the syringe 3. The external diameter of the boss is suilciently greater than that of the inner cylinder 2 so that the under surface thereof forms a shoulder which operates as a stop to limit the downward stroke of the inner cylinder 2.

`A releasable latch is pivotally mounted on the exterior surface of the cylinder I and operates to retain the inner cylinder 2 in its retracted position until the latch is moved to releasing position. The latch comprises a channel-shaped lever arm II which is pivotally mounted on the supporting brackets I2 positioned adjacent to the flanged portion 4 of the cylinder I and integral with the outer surface of such cylinder. The upper end of said lever arm is provided with an inwardly projecting portion I3 formed integral therewith which extends in through an aperture provided in the wall of the outer cylinder I and is adapted to engage with the under edge portion of the flange 1 on the inner cylinder 2 when such cylinder is drawn to fully retracted position. The inner end of the portion I3 is preferably rounded to enable it to ride over the coils of the spring 6 without catching. Seated in an annular recess I4 formed on the interior side of the flanged portion 4 of the outer cylinder is a circularly shaped spring member I5 which is tensioned so that it bears outwardly against the inner wall of the recess. 'I'he free end portions of the spring are disposed on either side of the side flanges on the upper portion of the vertical arm 32, as shown in Fig. 9, such flanges limiting the rotational movement of the spring. As shown in Figs. 2 and 9, one of the free end portions of the spring I5 bears outwardly against the channeled sides of the lower portion of the lever arm II which extend through a slot I'I provided in the fianged'portion 4 of the outer cylinder I. With this arrangement the projecting portion I3 of the lever arm II is maintained in contact with the outer surface of the inner cylinder 2 when the parts are in normal position. When the inner cylinder 2 is withdrawn to its retracted position preparatory to the use of the device the spring I5 yieldingly resists any inward movement of the lower portion of the lever arm I I caused by the projection I3 riding over the spring 6 and flange 1 of the inner cylinder and when the inner cylinder has been withdrawn to its fully retracted position the spring rotates the lever arm I I to position the projection I3 under the flange 'I'of the inner cylinder, as shown in Fig. 2, thereby maintaining the inner cylinder in its retracted position until it is released by the user pivoting the lever arm II against the tension of spring I5. Projections I8 are `integrally formed on each side of the lever arm II between the supporting brackets I2 and the flanged portion 4 of the outer cylinder and are adapted to engage the exterior surface of such cylinder and limit the inward movement of the lower portion of the lever arm. The outer surface of the lever II may be roughened in any suitable manner to provide a grip thereon for the user.

AThe syringe 3 comprises a barrel portion I8 provided with an integral ccllar or shoulder 3 at its upper end and an ejecting end 20 through which passes a discharge duct. Mounted on the ejecting end 20 is a needle 4hub 2| of the usual type provided with a needle 22. As shown in Fig. 1 the length of the barrel of the syringe and the length of the cylinders I and 2 are so related that a major portion of the syringe barrel extends below such cylinders when the parts are in normal or projected position. A scale 23 for indicating the amount of dosage is provided on the exterior surface of that portion of the syringe barrel which extends below the normally positioned cylinders I and 2. Thus by reason of this arrangement, the major portion of the syringe barrel is visible to the user when the needle has been projected into the patient and the visible scale enables the user to readily discharge the proper amount of medicament into the tissues penetrated by the needle without error.

A holder 24 is carried by the inner cylinder 2 for gripping and supporting the lower exposed portion'of the syringe barrel, such holder comprising an upper cylindrical section 25 which is sweated or otherwise attached to the inner periphery of the inner cylinder 2 so that it is securely retained in position in said cylinder. The cylindrical section 25 is preferably of a length suiilcient to solidly support the lower section 2B of the holder 24 which is integral therewith. The lower section 26o! the holder which is of a length substantially the same as that of the portion of the syringe barrel which extends below the inner cylinder 2, is disposed to the rear of the syringe barrel and is semi-.circular in cross-section so that when the syringe barrel is positioned in said lower section 2B, the latter does not interfere with the reading of the scale 23 on the syringe barrel.

'I'he lower end portion of the section 26 is provided with two substantially parallel slots 21 which extend longitudinally of the section and separate the lower edge portions 28 of the section from the body portion thereof so that. such edge portions are in the nature of longitudinally extending tongues or springs. The free ends of the lower edge portions or tongues 28 are provided with forwardly projecting arcuately shaped projections or toes 29 which are adapted to grip the syringe barrel as shown in Figs. l and 2. 'Ihe free endportion of each tongue 28 and its associaied toe 29 are turned inwardly adjacent their lower edges so that when the syringe is positioned in the device the tongues 28 are placed under a suflicient amount of tension to cause the free ends v thereof and the toes 29 to securely hold the lower end of the syringe against. transverse movement during the operation of the device. The lower edge portions of the tongues 28 and the toes 29 also seat against a shoulder 30 formed on the lower end of the syringe barrel and yieldingly s the arm 32 togbe positionedrin parallel'relation 'vertically disposed arm 32.

resists any upward movement of the syringe dur- I ing the operation of the device.

, Fixedly attached at its upper end to the outer surfaceof the cylinder Ivby thescrews3l is a A portionofgthe ange, 4 onthe cylinder l is removed to enable with the line of movement ofthe inner cylinder `2. A pair' offorwardlyprojecting lugs 33 are `integrally associated with theside edges `of the vertical arm 32 andare `positioned -intermediate the lower 4end of the latter and the flange 4 on the cylinder I. As shown` in Figs. lto 3, the lugs 33 are curved away from each other at their outer end portions toiform aseato-r guide on which the lower section v26 ofthe holder 24 slides when it is moved up and down with the inner cylinder 2.` The lugs 33 are` positioned on the arm 32 so that the section 26. ofl theholder 24 remains in contact therewith throughout its range of movement. Fixedly secured to the inner side i of the `vertical arm 32 immediately above. the

'guide lugs 33 is a pin 34 which is reduced in cross `section adjacent its outer end so thata head portion 35 is formed thereon. The reduced portion of the pin 34 extends through a slotv36 provided `in a longitudinallyfdisposed raised portion 31 ofthe lower section.26 of the holder 24,

'such `slot being of suicient length to permit the holder 24 to be drawn to its fully retracted po- 'sition'with the inner cylinder 2. The head portion 35 of the pin rides on the edgesof `the slot within the raised portion `31 so that it does not engage with the barrel of the syringe during the movement of the latter in the operation of the device; With this arrangement, the lower section'26 of theholder 24 which tightly grips and supports the lower'portionxof the barrel of the syringe,` is guided in its downward plunging motio-n by the guide lugs 33, pin 34 and slot 36 so that the needle of the syringe speeds straight to the fleshy area that is to be treated. Due to the fact that the guide lugs 33 preventiany rearward movement ofthe holder and the syringe 3'toward the arm 32, andthe pin 34 together with the slot 36 prevent any rotative movementof the inner cylinder 2V and the holder 24 relative-to the outer cylinder I, and the head portion 35 of the pin 'prevents anyniovement of the syringe and the holder awayfrom the arm 32, the syringe 3 isplunged downwardly under the influence of the `springt v with a minimum of vibration` of the syringe duringsuch movement.

"'I'helower end portion of J(he arm 32'isl provided with forwardly extending side flanges 38 with ywhich it is `adapted `to slidably receive the shank 39o`f a foot 40. The foot4ll maybe varied.

ywith r'eferencato the needle 22 to control the latte'rfs depth of penetration by loosening the nut "4|` carried by the screw 42 which-is fxedly mounted'on the .shank 39 as shown in Fig. 4. and moving the foot 'to the'desired/position.y A longitudinally extending `s1t"`43 in the lower end of the arm 32 enables the screw 42 to be moved with the shankw39` lengthwise of the arm 32.` When `thelfoot 40 has-been moved to the desired posiytion `the nut 4I is tightened against the rear side of the arm32 to hold the foctinthe adjusted position., The Lipper end of the shank 39 is pro- `videdv with ay longitudinally extending slot 44 ,wnerebythe upper ,end of the shank' is enabled to straddlethe'pin 34 the latter member operating as a stop to limit theupwardadjustment of The shoulder 9 at the upper end of the syringe barrel comprises two oppositely disposed straightportion-.5 ,2-for embracing the upper `portio'nfof thevbarrel, spring fingers 53 which are exed toward the .axis of the barrel and arefadapted to extend,y .around thejstraight-sided portions of the shoulder `9, and terminal portions 54 adapted to contact with the'outer surface of the plunger y5I and to brake its downward movement.

An annular member 56 of spring metal is seated in the bossli on the upper end of the inner cylinder2 intermediate the seating face thereof and the shoulder 9 on the upper yend of the syringe barrel, the external diameter of such annular member being approximately the same as the diameter of the inner wall/of the boss so that the member 56 ts snugly within the boss.` Integral with the outer peripheral edge of theannular disc are three small outwardly extending projections or lugs 51, 58,y and 59, the lug 51 being di-ametrically opposed tothe lugs 5B and 59 which arelpositioned relatively close to each other, as shown in Fig. 12. The lugs 51, 58, and 59` are adapted to be positioned in the apertures 60, 6|, and 62, respectively, which are vprovided in the annular wall of the boss 8. As is clearly shown in Fig. I6, .the aperture 60 which is adapted to receive the lug 51, is positioned in the front or forward portion of the annular wall of the boss `8 whilethe `apertures 6I and 62 which are adapted to receive the 'lugs 58 and `59, respectively, are positioned inthe rear portion of the annular wall of the boss. Thus it is seen that the` annular member 56 can only be seated in the boss 8 in one position, namely with the lug 51 to the front, of the device and lugs'` 58 and 59 to the rearof the device.v This arrangement makesjit possible to readily insert the syringe vin the device sorthat' it will bein its proper'position `for readingthefscale 23 on the yloarrel thereof during the operation. of the device as will be hereinafter explained. While the annular member 56 isshown asdbeingwflat so that itsentire undersurfacegsleats on the `seating face, of thev boss, it will` beunderstoodfthat theannular member 56` may be distorted or loentvsoI` that the` two diam'etrically opposed portions ofthe annular member `from'virhicl'i the projections` extend Seat on the boss while the remainder of the member is raised from the' seating face thereof in bowed fashion. In `this modified form, the annular member 56 is thus` spring-tensioned against any downward `movement of the, shoulder 9 vof the syringe which is seated on the raised portions ,thereof so that when the downward plunging of and .minimizes vibration of the needle in the nesh .of the patient. .Integrally associated with Figs. 4, 6, and 8.)

the inner edge portion of the annular member 56 and positioned on each side of the outwardly extending lugs 51 on said disc and vequally spaced therefrom are two upwardly projecting resilient members 64 and 65 which are adapted to cooperate with one of the oppositelyv disposed straightsided sections of the shoulder 9 to keep the syringe from turning during the operation of the device. As the annular member 56, by reason of the projecting lugs 51, 58, and 59 and the apertures 60, 5I, and 62, can only be positioned in the boss 8 so that the members 64 and 55 are positioned adjacent the front portion of the annular wall of the boss and as such members 54 and 55 are closer to the axis of the syringe barrel than the outer edge portions of the sections 48 of the shoulder 9, the syringe can readily be inserted in position in the injector so that the scale thereof is in proper position for reading and the above-mentioned parts operate to maintain the syringe in this position. The annular member is provided with diametrically opposed slots 55 through which the ilngers 55 of the clip 50 pass, thereby enabling the shoulder 9 to seat on the annular disc 55. In the construction of the annular member illustrated, the members 54 and 55 are positioned adjacent the side edges of the forward slot.

integrally associated with the annular member 55 and positioned intermediate the projections or fastening lugs 58 and 59 is an upwardly projecting spring member 61 which extends through a vertical slot 68 formed in the rear portion of the annular wall of the boss 8 so that its free end portion engages with the inner side surface of an annular locking ring or cover 59. (See The free end portion of the spring member 61 bears with suillcient pressure against the inner side surface of the cover to prevent turning of the cover while the injector is in use. The top portion of the cover has an opening therein which is substantially thesa'me shape as the top portion of the shoulder 9 on the syringe in order that the syringe may be positioned in or removed from the injector Without removing the cover. When the syringeis to be inserted in the injector the cover is in the position shown in Fig. '1, so that the shoulder 9 of the syringe can be passed through the opening in the top portion of the cover and seated on the boss 8. When the syringe is in position in the injector the cover is positively turned through an angle of ninety degrees against the frictional resistance caused by the spring member 51 bearing against the inner side surface of the cover until the oppositely disposed widened portions 10 of the top of the cover are over the two oppositely disposed sections 48 of the shoulder 9 at the upper endof the syringe barrel, thereby locking the syringe in position in the barrel. To remove the syringe, the cover is rotated back through ninety degrees until the opening in the cover is positioned as shown in Fig. '7, with respect to the shoulder 9 on the syringe. The rotative movement of the cover for the above-mentioned purposes is definitely limited by means of stops as will be now explained. Punched or stamped from the material'constituting the annular side wall of the cover are two tongues' 1| and 12, the free ends of (such tongues being disposed in opposite directions and extending inwardly a suilicient distance from the inner surface of the side wally 'of the cover to engage with an external groove 13 formed in the annular wall oi the boss 8. The inner wall of the groove is also provided with two tongues 14 and 15. The tongue 14 is disposed oppositely to the tongue 1l on the cover and extends outwardiy in the groove a suillcient amount to engage with the tongue 1I to limit the rotative movement of the cover in a clockwise direction. In a similar manner the tongue 15 is disposed oppositely to tongue 12 on the cover and cooperates with it to limit the rotative movement of the cover in a counter-clockwise direction. The sets of tongues or stops 1I, 14 and 12, 15 are so positioned with relation to each other that when the tongues 1l and 14 are in contact with each other, as shown in Fig. 6, the cover is in the position shown in Fig. 5 and locks the syringe in place in the injector, and when the tongues 12 and 15 are in contact with each other, as shown in Fig. 8, the cover is in the position shown in Fig. 7 and enables the syringe to be removed from the injector. Thus the extent to which the cover can be turned in either a clockwise or counter-clockwise direction is limited to ninety degrees. The inwardly projecting tongues 1I and 12 on the cover also cooperate with the groove 13 on the boss 8 to permanently maintain the cover in place on the boss 8. The top edge 15 of the boss 8 is preferably beveled to enable the cover to be readily assembled on the boss, the tongues 1I and 12 readily sliding over such beveled edge into place in the groove 14 as the cover is placed in position on the device.

In operating the injector, it is readily understood that the inner cylinder 2 is retracted to a position so that the inwardly projecting portion Il of the lever Il engages with the lower side of the outwardly extending ange 1 on the lower end of the inner cylinder to hold the inner cylinder 2 in retracted position. When the foot 40 has been placed in position on the body of the patient, the lower end of the lever Il is pressed down, thereby releasing the inner cylindr 2 which plunges downward under the inuence of the spring 5 to plunge the end of the n needle 22 into the body of the patient to the desired depth. In their downward motion the holder 24 and the syringe 3 are guided by the guiding lugs 33, the pin 34 including its flattened head 35 and the slot 35, such parts also operating to hold the holder 24 and syringe 3 suillciently steady so that there is virtually no vibration of the syringe barrel or the needle during such downward motion vor at the end of their stroke.

While I have illustrated and described the preferred embodiment of the invention it will be readily understood that various changes in the form, construction and arrangement of the various parts of the invention may be resorted to without departing from the scope of the inven tion, hence I do not wish to limit myself strictly to the structure herein set forth.

I claim:

1. An automatic syringe injector comprising an outer hollow cylindrical member, an inner hollow cylindrical member positioned in said outer cylindrical member and adapted to reciprocate within the latter, a syringe having a anged shoulder at its upper end extending through said inner cylindrical member, means provided on the outer end of said inner member for engaging the shoulder of the syringe to hold the syringe in position therein, said syringe being substantially greater in length than said cylindrical members so that a major portion of the syringe barrel projects below the lower edge portions of said members in the normal position of the latn ter, a graduated scale provided on the exposed projectmg end portion of Ithe-syringebarrel intermediate the lower end of said barrel/andthe Vlower edge portions ofk saidv cylindrical membersl member being so formed and so arranged with relation to the syringe barrel `that it doesnot interfere with the reading of the graduated scale and being providedat its lower end with yieldable friction means adapted to grip the lower' end portion-of the syringe barrel; afspring for normally holding vsaid cylindrical members one within the other and adapted to exert-tension on the inner cylindrical member when the latter is retracted from Vsaid outercylindrical'member, and means for holding saidl inner cylindrical member in retracted position.

x 2. An automatic syringe injector comprising an outer hollow cylindrical member, an inner hollowA cylindrical member positioned in 4said outer cylindrical `member and adapted to reciprocate within the latter, said inner cylindrical member being adapted to receive and support the barrel of a syringe, a springfornormallylholding said cylindrical members one within the other and adapted to exertltension on the inner cylindrical member when'the latter is retracted from said outer cylindrical.` member,

means for holding said inner cylindrical member f in' retracted position, said means 'comprising an aperture in the wall of said outer cylindrical member,` a lever pivotally supported on said outer cylindrical member and having an inwardly projecting portion adapted toproject through the aperture in said outer cylindrical member and engagewith said inner cylindrical member to hold the latter in retracted position, an annular groove formed in the interior surface of said outer cylindrical member, a circularly formed spring positioned in said annular groovel and an opening in the wall of said outer cylindrical member touenable a free end `portion of said spring to engage said lever and normally hold the projectingportion thereof against exterior Wall of said inner cylindrical member. K e

M3. An automatic syringe injector such as dened `infclaim 1 in which the holding member.

isy provided at its lower yendwith afplurality. of longitudinally extendingrtongues, the lower ,end portionslof said tonguesbeing adapted to tightly grip the-lower portion of the-projecting syringe barrel. l 1

4. An automatic syringe such as .dened in claim l in which the holdingrmember comprises .an upper tubularportion securely supportedon the inner wall of saidinner cylindrical `member and a lower portion integral withfsaid upper `portion and positioned exteriorlyv of said cylindrical member and adjacentto the outer surface ofthe syringe barrel, said lowerportion being slotted at its lower end to form a pluralityv of `longitudinally extending tongues, the lower ends of said tongues being bent inwardly tol frictionally engage with the lower portion -of the syringe barrel.

5. An automatic syringe injector' comprising an outer hollow cylindrical member, an innerhollow cylindrical member positioned within said outer cylindrical member and adapted to reciprocate within' the latter, a syringe supported at its upper end portion within said inner cylindrical member,

ing a guide adaptedto tudinal slot. i

said syringe being substantially greater in length thansaid cylindrical members so that a major bythe outer cylindrical member adapted to guide the movement of said longitudinal holding member, a spring for normally holding said cylindrical members one within the other and adapted to exert tension on the inner cylindrical member when the latter is retracted from said outer cylindrical member, and means forv holding said inner cylindrical member in retracted position.

6. An-automatic syringe injector such as deilned in claim 5 inwhich the means carried by the outer cylindrical member for guiding the movement of saidA longitudinal member comprises an arm extending longitudinally of the syringe in parallel relation with said-longitudinal member and securely fastened at.its upper end to said outer cylindrical member, said arm having a pair of guide lugs adapted to slidably engage with the exterior surface of said longitudinal member throughout its range of movement and to prevent movement of said longitudinal member toward-said arm.

v'7. An automatic syringe injector such as defined in claim 5 in which the longitudinal memberl is serni-circular in cross-section and the means carried by the outer cylindrical member` for guiding the movement of said member comprises an arm `extending longitudinally of the syringe in parallel relation with said longitudinal member and securely fastened at its upper end to said outer cylindrical member, a pairof guide lugs integral with said arm and adapted to slidably engage with the exterior surface of said longitudinal member throughout its range of movement, the engagingportions of said extensions being arcuatelyshaped so as to forma. cradle for the `semi-circular outer surface of` said` longitudinal member yand prevent .movement Vof said longitudinal member toward said e 8. Anautomatic syringe injectorsuchfas del-M -fined in claim 5 in which said holding member -is provided with a longitudinal slot and themeans carried bythe outer cylindrical member for-,guidin g the movement of said holding member comprises anarm extending longitudinally of the syringe in fparallel relation with said longitudinal member and securely fastenedatitsupper end to said outer cylindrical member, said arm carryengage with said longiv9. An automatic syringeinjector such asj-vde fined'in claim 5` in` which said holding member is provided with a longitudinal slot and the means carriedby the outer cylindrical member for-guiding the movement of said.- holding member coma l prises an arm extending longitudinally of the syringe in parallel relation with said longitudinal member and securely fastened at its upper end to said outer cylindrical member, said armearrying a pin extending through said slot and adapted to preventrotative movement `of said longitudinal member and said inner cylindricalmember relative to'said outer cylindrical memberysaid pin having a head portion adapted'to engage with the side portions of the slot and prevent movement of said longitudinal member away from said arm.

10. An automatic syringe injector such as deilned in claim 5 in which said holding member is provided with a longitudinal slot and the means carried by the outer cylindrical member for guiding the movement of said holding member comprises an arm extending longitudinally of the syringe in parallel relation with said longitudinal member and securely fastened at its upper end to said outer cylindrical member, means carried by said arm and adapted to engage withsaid slot to prevent rotative movement of said holding member, means carried by said arm adapted to slidably engage with one side of said holding member to prevent movement of the latter in one direction, and means carried by said arm adapted to slidably engage with the opposite side of said holding member to prevent movement of the latter in the opposite direction, all of said parts cooperating to prevent vibration of said holding member and said syringe in their downward plunging motion and to guide the needle straight to the place to be penetrated.

11. An automatic syringe injector comprising an outer hollow cylindrical member, an inner hollow cylindrical member positioned within said outer cylindrical member and adapted to reciprocate within the latter, said inner member having an expanded annular portion at the upper end thereof adapted to seat on the upper edge portion of said outer member, a syringe having a anged shoulder at its upper end adapted to seat in said expanded annular portion, said syringe being substantially greater in length than said cylindrical members so that the major portion of the syringe barrel projects below the lower edge portions of said members in the normal position of the latter, a graduated scale provided on-the exposed projecting end portion of the syringe barrel intermediate the lower end of said barrel and the lower edge portions of said cylindrical members, means associated with the expanded annular portion of the inner cylindrical member and the shoulder on said syringe to operate as a positioning means for the syringe, a spring for normally holding said cylindrical members one within the other and adapted to exert tension on the inner cylindrical member when the latter is retracted from said outer cylindrical member, and means for holding said inner cylindrical member in retracted position.

12. An automatic syringe injector such as defined in claim 11 in which said positioning means comprises an annular member positioned intermediate the seating face of said expanded annular portion and the shoulder on said syringe and having an upwardly projecting extension adapted to engage with a predetermined portion of the syringe shoulder, and means for locking said annular member in a predetermined poisition in the seat of said expanded annular portion whereby the position of the syringe shoulder is iixed with respect to the expanded -annular portion of the injector.

13. An automatic syringe injector such as defined in claim l1 in which said positioning means comprises an annular disc positioned intermediate the seating face of said expanded annular portion and the shoulder on said syringe and having an upwardly projecting extension adapted to engage with a predetermined position of the syringe shoulder, a plurality of projections extending outwardly from the peripheral edge of said annular disc, and an equal number of apertures in the annular wall of said expanded portion adapted to receive said projections whereby the position of the syringe shoulder is iixed with respect to the expanded annular portion of the injector, said projections and apertures being so positioned relative to the upstanding projecting extension of the annular disc that when said extension is in engagement with the syringe shoulder the syringe is secured in the injector with the graduated scale thereon in proper position for reading. l

14. An automatic syringe injector comprising an outer cylindrical member, an inner hollow cylindrical member positioned within said outer cylindrical member and adapted to reciprocate within the latter, said inner member having an expanded annular portion at the upper end thereof adapted to seat on the upper edge portion of said outer member, a syringe having a flanged shoulder at its upper end adapted to seat in said expanded annular portion, said shoulder having at least one edge portion which is positioned at a different distance from the axis of the syringe than the remaining edge portion thereof, a cover rotatably mounted on the annular wall of said expanded annular portion and permanently secured thereto, said cover having I an opening which is so formed relative to the syringe shoulder, that in one position of the cover the syringe is securely held in said injector, While in another position of said cover the syringe may be removed from the injector, a spring for normally holding said cylindrical members one within the other and adapted to exert tension on the inner cylindrical member when the latter is retracted from said outer cylinder, and means for holding said inner cylindrical member in `re tracted position.

15. An automatic syringe such as defined in claim 14 in which the expanded annular portion is provided with a slot in the annular Wall thereof, and an annular disc member positioned intermediate the seating face of said expanded annular portion and the shoulder on said syringe and having an upwardly projecting extension integral therewith, said extension projecting through the slot provided in the wall of the expanded annular portion and frictionally engaging with the side wall o1' said cover toprevent free rotation of the cover. l

16. An automatic syringe such as defined in claim 14 in which the expanded annular portion is provided with an external annular groove and a member extending from the inner surface of the side wall of the cover and engaging with said groove to permanently secure the cover on said expanded annular portion while enabling rotational movement thereof. l

17. An automatic syringe such as dened in claim 14 in which the expanded annular portion is provided with an external annular groove, a pair of spaced members extending from the inner surface of the side wall of the cover and engaging with the groove to permanently secure the cover on. said expanded annular portion while enabling rotational movement of said cover, and means cooperating with said spaced members for limiting the rotational movement of said cover. y

18. An automatic syringe injector comprising an outer hollow cylindrical member, an inner hollow cylindrical member positioned within said outer cylindrical member and adapted to reciprocate within the latter, a syringe supported at its upper end portion within said inner cylindrical' member, said syringe being substantially greater in length than said cylindrical members so that a major portion 0f the syringe barrel projects below the lower edge portion of said members in theV normal position of the latter, a graduated scale provided on the exposed projecting end portion of the syringe barrel intermediate the lower end of said barrel and the lower edge portions of said cylindrical members, said syringe having an outwardly extending portion formed on the lower projecting portion of the syringe barrel, a holding member extending longitudinally of the syringe and mounted at its upper end on the inner cylindrical member, said 'holding member being provided at its lower end with a yieldable gripping means adapted to cooperate with the lower portion of the syringe and the outwardly extending portion formed on said syringe to prevent displacement of the syringe during the operation of the device, a spring for normally holding said cylindrical members one within the other and adapted to exert tension on the inner cylindrical member when the latter is retracted from said outer cylindrical member 'and means for holding said inner cylindrical member in retracted position.

FAIRLEIGH S. DICKINSON. 15 

